Charles a



(No Model.) 0. A. VAN ALLEN.

:SPRING FOR KEEPING PITMEN OFF DEAD CENTERS. No. 287,485. Patented 0013. 30, 1883.

N. PEIERS. Phclnlilhugrzpher. Wmhinglvn. 0.8.

' INITED; STATES PATENT CHARLES A. V N ALLEN, OFOHIOAGO, ILLINOIS, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO THE- vAN ALLEN MANUFACTURING COMPANY, OF SAME PLACE.

SPRING FOR KEEPING PITME N OFFDEAD-CENTERS.

SPECIFICATION forming part of Letters Patent No. 287,485, dated October 30, 1883.

Application filed July 11,1883. (NomodelJ To all whom it may concern:

Be it known that I, CHARLES A. VAN AL- LEN, a citizen of the United States, residing in the city of Chicago, county of Cook, and

5 State of Illinois, have invented certain new and useful Improvements in Springs for Keeping Pitmen off Dead-Centers, of which the following is a specification.

This invention relates to an improvement 1 in the compound spring for throwing pitmen off their dead-centers, secured to me by Letters Patent of the United States No. 254,248. The object of my present improvement is to adapt a compound spring for a like, purpose to machines running in reverse directions, and varying in structure and dimensions; also, to provide means for adjustably securing the spring upon the pitman and some stationary part of the machineas, for example, the treadle-axle or the table-supporting frame and to admit of the tension upon certain portions of the spring being regulated. A further object is to improve the construction of the spring, and to provide means for avoiding loss of power by limiting the extent to which one I of the coils can be expanded, all as hereinafter fully described, and illustrated in the annexed drawings, in which Figure 1 is a side elevationof my compound spring attached, and illustrates the pitman on the upper dead-center. Fig. 2 is alike view, showing a slight variation in the manner of arranging and attaching the spring. Fig. 3 is an enlarged perspective view of the attaching 3 5 device for the lower end of the spring, secured to a portion of a sewing-machine frame. Fig.

4. is a side elevation of the lower end portion of the compound spring, connected to an attaching device that is secured upon thetreadle- 4o axle. Fig. 5 is atop or plan view of the devices shown in Fig. 4. Fig. 6 is a top or plan view of an attaching device for the upper end of the compound spring secured to the pitman, which latter is shown in cross-section. V The dotted lines, Figs. 1 and 2, are intended to illustrate the position of the parts when the pitman is on the lower dead-center.

The compound spring illustrated in the annexed drawings consists of a spring-wire bent to form a spring-coil, A, from the end of which latter the wire extends tangentially to the coil,

so as to provide two diverging spring-arms, B and O, which are bent near their ends to form the two spring-coils D and E. This compound. spring, which will be arranged in a substantially vertical plane below the ma-v chine-table, has its lower terminal, beyond coil E, 'adjustably connected with an attachment susceptible of a variety of adjustments, and detachably secured upon some stationary part of the machine, whilethe upper terminal of the compound spring, beyond the upper coil, D, is adj ustably connected with a swivel carried by an attaching device, that is in turn adjustably secured upon the pitman. This mode of adjustably connecting the compound spring with attachments which are respectively held 1 in adjustment upon the pitman and some suitable stationary part of the machine subserves the twofold purpose of allowing the compound spring to be placed and held upon any construction of machine inv proper position for normally holding the pitman off the dead-center when'the machine is at rest, and for regulating the tensions upon the component parts of the compound spring, especially the upper coil, D, so that said members shall efficiently perform the functions for which they are designed.

The means for attaching the upper terminal, 11, of the compound spring to the pitman consists of a swivel, F, that is adapted to be adjustably'secured upon the pitman. This clamp is conveniently formed of two plates, F', bolted together, whereby the plates can be set at the required height upon the pitman preparatory to tightening up the bolts or screws. The up means for attaching the lower terminal, 6, of

machine, consists of a clamp, G, carrying an one or more set-screws, whereby the plate can be adjusted to various positions upon the clamp. This arrangement admits of said attaching device being secured to any construction of machine, whereby the same size of I 5 compound spring can be applied to machines varying in structure or dimensions. The terminal e of the compound spring can be secured directly to the adjustable plate H, as in Fig. 3; or it can be secured in aknob or swivel, K, provided with a binding-screw, K, for bolding the wire. and connected with the slotted plate.

In order that my compound spring shall be effective on machines working in different direc'tionsas, for example, as in Figs. 1 and 2, in which the arrows alongside the driving or belt wheels L (shown in dotted lines) respectively indicate the direction of their forward revolution-some slight changes in the construction and arrangement of the spring become necessary. Referring now to Fig. 1, it will be seen that the upper terminal, b, of the compound spring crosses the upper springarm at a point below the coil D, and that the spring-arms B and Cr are connected together near the middle coil by a chain or loose link,

M, that will allow the spring to be contracted to any required extent, but serve to prevent its being expanded or uncoiled beyond a cero tain limit, and thereby prevent loss of power,

as will be hereinafter set forth. In Fig. 2, however, the upper terminal, I), of the compound spring does not cross the upper springarm, and in lieu of connecting together the 5 spring-arms by a link, the lower arm, 0, is

connected by a chain, m, that is attached to the slotted plate of the attaching device se' cured upon the machine stand or frame. This chain serves to hold down the compound spring in position to maintain the pitman off the upper dead-center; but, if preferred, the

chain could be dispensed with and the two arms connected together by a chain or link, as

in Fig. 1.

As will be hereinafter seen, when the compound spring is applied to a machine in which the band-wheel has its forward revolution in the direction of the arrow, Fig. 1, the middle spring-coil, A, carries it past the lower dead- 6 0 center, and the lower spring-coil, E, which is esmss ona machine in which the balance-wheel revolves forward in a direction reversely to that in Fig. 1, the upper coil, D, serves to throw the pitman off the lower dead-center, the middle coil, A, to throw it off the upper dead-center, and the lower coil, E, to assist in contracting the middle coil after the pitman has passed the lower and before it has reached the upper dead-center. Such action on the part of these compound springs will be more fully understood from the following: In Fig. 1 the pitman is represented in full lines on the upper dead- ,center, and the two extreme positions of the compound spring for throwing the pitman off its upper and lower dead-center respectively indicated in full and in dotted lines. The line 1 2 also illustrates substantially the position in which the pitman will be thrown from off the upper center by the spring, and in which the pitman will be maintained while the machine is at rest and the compound spring in its normal condition. As the wheel isrevolved forward in the direction of the arrow the lower spring-arm, C, will be depressed, and the coil E contracted until it reaches, or nearly reaches,

ward the lower spring-arm, thereby contract- I ing the middle coil, A, whereby when the pitman arrives at the lower dead-center the expansive force of the middle coil, A, will carry the pitman past such point. As soon as the pitman passes the lower dead-center the expansive force of the lower spring-coil, E, comes into action, and, through the medium of the entire spring, exerts its entire influence upon the pitman, moving round to the upper dead-ecu ter, so as to cause theupper coil, D, to contract until at or about the time the pitman reaches the upper center, at which moment coilD will expand and throw the pitman past the upper center. After the spring-coil A has expanded to the required extent for carrying the pitman past the lower dead-center, further expansion on the part of said coil while the upper coil, D, is contracting will be prevented by the link connecting the spring-arms, and hence loss of power prevented, and the arm B.held in connection with the lower spring-arm, so that while the pitman is passing on to the upper dead-center the contraction of the upper coil, D, shall be insured. When, however, the compound spring is applied to a machine, as in Fig. 2, in which the wheel revolves forward reversely to that in Fig. 1, the compound spring will be in its normal position'when the pitman is off the upper dead-center and on the line 2 3 at the left of the same. As the wheel in this instance revolves forward, carrying the pitman past the line 2 3, the upper and lower coils, D and '0, contract, so that when the pitman reaches the lower dead-center, as shown in dotted lines, the expansive force of the upper. coil, D, will carry the pitman past the lower dead-center, and after such moment the expansive force of coil E will tend to raise the pitman, and thereby contract-the middle coil, A, which latter, when the pitman reaches the upper dead-center, exerts its exthe two.

'pansive force to throw the pitman past such point. The chain M will be slackened up while the pitman is in its lower positions, as shown in dotted lines, but will be taut, and exert sufficient tension on arm 0 when the pitman is in its upper positions to hold the pitman onor about on the line 2 3, which, it will be remem-- bered, is at one side of the dead-center.

In constructing this compound spring the two end spring-coils are preferably stronger than the middle spring-coil, which variation in strength can be readily effected by varying the number of convolutions in the coils.

In Fig. 1 the two spring-arms are substantially equal in length, while in the compound spring shown in Fig. 2 I have found that the lower spring-arm, 0, should be the shorter of It will be seen that by increasing or decreasing the length of wire between the upper coil and the pitman in Fig. 1 the tension on said coil can be varied, and that this said portion of the wire constitutes a short'strong arm ,which, while the pitman is passing from the lower to the upper dead-center, insures the winding of such coil against the resistance of the remaining portions of the compound spring. The same-result is practically attained in Fig. 2, in which the short upper end of the wire be yond the upper coil is adjustably connected with the pitman.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, 1s

1. The combination, with a compound spring adapted to throw a pitman off its dead-centers, substantially as described, of devices for connecting said compound spring with the pitman and some stationary part of the machine, whereby the spring can be applied to machines of various construction.

2. The combination, with a compound spring adapted, substantially as described, to throw a pitman off its dead-centers, of an attaching device adapted to be secured to the pitman,

and constructed so that one end of the compound spring can be adjustably connected with p said attaching device, whereby tension upon the upper spring-coil can be regulated, for the purpose set forth.

3. The combination, with the herein described compound spring adapted to throw a pitman off its dead-centers, of an attaching device which is adapted to be secured in a position upon the pitman, and provided with a swivel, to which one end of the compound spring is adjustably connected, substantially as set forth. I

4. The combination, with a compound spring adapted, substantially as described, to throw a pitman off its dead-ccnters, of an attaching device for the lower end of the spring, adapted to be secured to some stationary part of the machine, and adj usted so as to bring the spring in proper position relatively to. the pitman, substantially as and for the purpose set forth.

5. The combination, with the hereindescribed compound spring adapted to throw a pitman off its dead-centers, of the attaching device, consisting of a clamp, G, carrying an adjustable slotted plate, with which the lower end of the compound spring is connected, substantially as described.

6. The combination, with the herein described compound spring connected with the pitman and some stationary part of the machine, of the link connecting the two springarms at points near the middle coil, for the purpose set forth.

CHARLES A. VAN ALLEN.

Witnesses:

WV. W. ELLIOTT, JNo. G. ELLIOTT. 

